title: Differences in plasma and sputum biomarkers between COPD and COPD-asthma overlap.
abstract: The pathophysiological features of chronic obstructive pulmonary disease (COPD)-asthma overlap are poorly understood and there has been no study of plasma or sputum biomarkers in overlap patients. In order to clarify the similarity and differences between overlap and COPD or asthma, we have investigated four potential biomarkers of COPD: surfactant protein A (SP-A), soluble receptor for advanced glycation end-products (sRAGE), myeloperoxidase (MPO) and neutrophil gelatinase-associated lipocalin (NGAL). SP-A and sRAGE are pneumocyte-derived markers. MPO and NGAL are neutrophil-derived molecules, but NGAL can also be expressed by respiratory epithelial cells. Plasma levels of SP-A and sRAGE and induced sputum levels of MPO and NGAL were measured by enzyme immunoassay/ELISA in 134 subjects: nonsmokers (n=26), smokers (n=23), asthma (n=32), COPD (n=39) and COPD-asthma overlap patients (n=14). In patients with COPD-asthma overlap, sputum MPO and plasma SP-A were significantly elevated whereas plasma sRAGE levels were reduced compared with asthma patients. Only sputum NGAL was significantly elevated in COPD-asthma overlap compared with COPD (p=0.00016) and could be used to differentiate patients with overlap from those with COPD. Increased induced sputum levels of NGAL might be a characteristic feature of overlap, suggesting enhanced neutrophilic airway inflammation and/or airway epithelial injury in COPD-asthma overlap.
authors.affiliation: Pulmonary Division, University of Helsinki and Helsinki University Central Hospital, Helsinki.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwamoto
authors.forename: Jing
authors.initials: J
authors.lastname: Gao
authors.forename: Jukka
authors.initials: J
authors.lastname: Koskela
authors.forename: Vuokko
authors.initials: V
authors.lastname: Kinnula
authors.forename: Hideo
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Tarja
authors.initials: T
authors.lastname: Laitinen
authors.forename: Witold
authors.initials: W
authors.lastname: Mazur
mesh_terms: D000209:Acute-Phase Proteins; D000328:Adult; D000368:Aged; D001249:Asthma / Q000097:blood* / Q000150:complications; D015415:Biomarkers / Q000097:blood* / Q000378:metabolism*; D002454:Cell Differentiation; D015897:Comorbidity; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D009195:Peroxidase / Q000097:blood; D011518:Proto-Oncogene Proteins / Q000097:blood; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood* / Q000150:complications; D037662:Pulmonary Surfactant-Associated Protein A / Q000378:metabolism; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000378:metabolism; D012907:Smoking; D013183:Sputum / Q000378:metabolism*
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D037662:Pulmonary Surfactant-Associated Protein A; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; C445842:SFTPA1 protein, human; D009195:Peroxidase